Marge Anderson, the longtime leader of the Mille Lacs Band of Ojibwe who led the tribe during its successful efforts to reclaim its tribal hunting and fishing rights and steered casino profits to social programs instead of individuals, has died. She was 81.

Anderson, the first woman to lead an American Indian tribe in Minnesota, died of natural causes Saturday on the band’s reservation in Onamia, according to the tribal government. Officials said she was an authority on the history, traditions and culture of the Ojibwe and was fluent in the language.

She also led the tribe into the modern era of American Indian gaming while she was the band’s chief executive from 1991 to 2000, and again from 2008 to 2012. She used the profits from the band’s Hinckley and Mille Lacs casinos to fund social programs, schools and clinics for the band’s members instead of handing out payments to individual members.

According to the band, more than 2,300 of its 4,300 members live on the reservation, which is about 75 miles north of Minneapolis.

“Marge Anderson was a great tribal leader for the band and a trailblazer for all of Indian Country,” Melanie Benjamin, the tribe’s current chief executive, said in a statement. “This is an extraordinary loss for the band.”

“Marge led the band through our treaty-rights case and into the modern era of Indian gaming,” added Curt Kalk, the band’s secretary-treasurer. “She made history for the band and we will feel her impact for generations.”

Anderson became a lightning rod for criticism by non-Indians when the tribe sued to reassert its fishing and hunting rights on Mille Lacs Lake and in other parts of east-central Minnesota that were granted under an 1837 treaty.

“This case is about more than hunting deer and catching fish,” she said shortly before the U.S. Supreme Court ruled in favor of the tribe in 1999. “It is about preserving and passing along the traditional ways that make us who we are — Ojibwe people.”

And she led a celebration outside tribal headquarters when the high court declared that the 1837 treaty was still valid.

“Today the United States has kept a promise,” Anderson said. “A promise that our rights are not just words on paper. A promise that agreements are made to be honored, not broken.”

Anderson is survived by her husband, Merlin Anderson, two children, six grandchildren and four great-grandchildren. A wake is planned for Tuesday evening, followed by a funeral Wednesday morning at the District I Community Center in Onamia.